Air or gas cleaning apparatus



Jan. 22, 1952 T.' w. CARRAWAY AIR OR GAS CLEANING APPARATUS 3 SheetsSheet l Filed May 21, 1948 4 INVENTOR. ffiomasMC'armwagy,

Jan. 22, 1952 T. w. CARRAWAY AIR OR GAS CLEANING APPARATUS 5 Sheets-Sheet 2 Filed May 21, 1948 INVENTOR.

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Jan. 22, 1952 1. w. CARRAWAY AIR 0R GAS CLEANING APPARATUS Filed May 21, 1948 3 Sheets-Sheet 3 MN Jl QM NR YQM Q A N INVENTOR.

T/zomas Carraway,

BY I AKA/M,

Patented Jan. 22, 1952 UNITED STATES PATENT OFFICE AIR R GAS CLEANING APPARATUS v Thomas W. can'awam DallaspTcx.

Application May 21, 1948, Serial No. 28,432

. 14 Claims.

This invention relates to air orgas cleaning apparatus and more particularly to air or gas cleaning apparatus of the kind in which air or gas is moved, e. g., by a blower or fan, through a cleanin chamber in which it is contacted by difiused water or other cleaning fluid which'removes the dust or solid particles. In apparatus of this class, the air or gas may enter the cleaning or dust removal chamber tangentiallyso as the cleaning chamber to drain off or evap'orate-,-a residual deposit of dry dust particles may be left on the impeller. If the particles are of a highly explosive nature, such as particles of TNT removed from the air in a munitions factory, and if the impeller is again placed in op eration before the residual particles are thor-" oughly washed away or wetted, dry explosive particles may be thrown off the impeller and against the chamber walls, resulting in an explosion.

In the copending application of Thomas W. Carraway, Serial No. 586,986, filed April 6, 1945, now Patent No. 2,539,344, issued Jan. 31, 1951, there is disclosed and claimed air or gas cleaning apparatus of the character referred to above, and which includes or is combined with mechanism for controlling the operation of'the dust removing equipment so as to eliminate the danger of dust explosions occurring in the apparatus itself.

The control equipment disclosed in the copend-- ing application operates so as automatically to eiiect thorough wetting of the inside of the wall of the cleaning chamber and .all parts inside the chamber before the mechanically movable'parts in the chamber begin to operate, and so as auto-I matically to effect delivery of fresh, clean washin'g fluid to the impeller fora predetermined period following actuation of a manually operated switch, push button or the like for stopping the operation of the entire apparatus.

An object of the present invention is to provide air, or gas cleaning apparatus of the kind gen erally referred to above, and which is automatically controlled-or operated so that'the starting of the blower or fan will be preceded to a predetermined extent by operation of a rotatable impeller which supplies the spray or diffusion of cleaning fluid in the cleaning chamber, thus assuringthat the interior of the chamber and the parts contained in the chamber will be wetted and forcibly washed thoroughly beforeair or gas ismoved through the chamber.

.Another object of the invention is to provide. improved means for. controlling or operating the several parts of the air or gas cleaning equipment in accordance with a predetermined plan, sequence,or timing. 7. 7

Other objects of theinvention, will become apparent from a reading of. the following detailed description, the appended claims, and the accompanying drawings, in which: 7

Figure 1 is, a .vertical section through part of a building equipped with apparatus embodying the invention, parts of the apparatus bein shown in section-and other parts in elevation;

Figure 2-is afragmentary view drawn on an enlarged scale, partly in section and partly in elevation, showing a fluid" coupling and associated parts for'transmitting drive to a blower;

Figures 3 and 4 respectively, are elevations of i check valves;

Figure 5 is a view partly in elevation and partly insection of asolenoid-operated fresh fluid supply control valve;

Figure 6 is-a detail, perspective view with parts broken away,'showing a preferred form of float switch equipment; and

Figure 7 is a Wiring diagram.

An illustrative embodiment of the invention is shown as being installed in a building includ-' ing a 'flo'or I and walls 2 and 3 which define a work room 4 and apparatus room 5. A table 6 located inlthe work room '4 may be used for doing that the air or gas enters the chamber 9 tangentially. r i i Closelyi related to and preferably supported on the top of the chamber ,5 is a blower l0 driven 3 by an operating motor I I for moving air through the chamber 9 and discharging it through a duct l2. If desired, another intake duct I3 may be arranged to draw in air from an upper level in the room 4 and deliver it to the cleaning chamber 9 by way of the main intake duct 8 in proportion determined by setting of a damper I4.

Because the air or gas enters the bottom of the cleaning chamber 9 tangentially, it will swirl spirally as it moved. upwardly by the blower l0. During its'swirling ascent the air or gas is subjected to the action of a cleaning fluid, for example, water, which is delivered to the interior of the chamber 9 in diffused; condition. for: contact with the air or gas and the entrained dust or solid particles. The mechanism for de-. livering and diffusing the cleaning ;fluid within the chamber 9 comprises a hollow shaft 15 coupled to the blower H1 in a manner to be described later, and a plurality Qfiyertically spaced im- P6 115; L otatable. ith. the. shaft 2 3. he: ot,- m. shaf bearine IT s. con tructed nd; aled. in. any. suitabl manner; to. p r it; the 110m of; cleaning fluid up thro h heho low-shaft from. a recirculationpipe L8. fedwi hfluid un r pres.- sure by a pump. l9v driven by. an. operatinem top 20. Eresh or non-recirculated washing fluid. may be delivered from. a. pipe. 21. tothe pipe [8. and into the hollow shaft. l5- under. the, control of a. normally closed. solenoidroperated. valve. '22.- for a. purposeto be described later..

A check. valve 23in. the. pipe line: [8; permits the flowof. recirculated fluid from. the pumpto. the shaft l5 but not reversely, andtacheclt. valve 24in the pipe 2 l' permits the flow. of fresh cleaningfluidfromthe valve 22.. tothe shaftv I5, but not. reversely.

In order to prevent-entrained. droplets of-waten or cleaning liquid from entering the. blower IO- and being. carried; out through. the discharge duct. l2, one or-more filters Z5..comp rising. matted minute glassorthe. likestrands or.- fibresmay. be. mountedin the upper; end of the. chamber 9..

The; impellers... 1.6.:. may.- vary. as. to the r specific onstruction. but; preferably. are so. arranged. that they commun cate; w h. he mteriqh c he, shaft. I5, 9; ha lu d livereds und r pres ure. within the shaft will be sprayed out into thechamber- 9. h n he s a a mp ller rc-s ationary. a willbe throwncentrifugally outwardly when the shaft and impellers are rotating, Theimpellers. may be constructed for example, as shown, in Pat. No. 2,239,3 l4preferred to above.

The larger particles of cleaning fluidwill impinge upon the filters. 25. and the. wallsjof the chamber 9, and willfdjrain into a collectiing basin 2B at the bottom of the chamber. For. economical'reasons itiis desirable to reuse'the cleaning fluid, but before reuse the collected dust; andsolid particles should be removed from the fluid. In the. illustrative embodiment of the invention, the used cleaning-fluid collected-in the basin 26flows downwardly through areturn; pipe- 2] and: is. delivered to a suitable separating equipment such as a decanter28 shownin Figure-1; The decanter equipment includes three chambers 29, 3-0 and 3i and downwardly extending baffles 32; The fluid moves quietly fromright to left from onechamber into the next, permitting the dust or solid particles toprecipitate and collect in the bottoms of the chambersina. well knownman ner. Fluid which has passed the-bafiie-32at the left hand chamber 3| encounters a screen 33.;atthe end of an intake-pipeconnectionfl 'lead ingtothepump l9:

In the normal operation of the equipment thus far described the pump l9 and blower l0 will run continuously. Recirculated fluid from which most of the dust and solid particles have been separated by the decanter 28 will be forced by the pump l9 through the pipe l8 and hollow shaft 15, and thence outwardly through the rotating impellers l6 for intimate contact with the air or gas swirling upwardly through the chamber 9. The dust andsolid particlesin-the air or gas will adhere to the-moistu-re particles which, upon impinging on the filters 25 or the walls of the chamber 9 will drain to the collecting basin 26, and then be returned through the pipe 21 to the decanter 28 for re-cleaning.

Some moisture will evaporate in the chamber B and. some few particles of unevaporated moisture may be carried past the filters 25 and discharged through the duct I2. In order to replenish the supply of cleaning fluid in the recirculation system the valve 22. is. opened from time to time; to: permit fresh cleaning fluid to,

flow intothe, hollow-shaft l5 and out through theimpellers ii. The opening and closing of the. valve 22 formaintaining a proper fluid level inthe decanter oft-reservoir 28-is controlled automatically by means to be described hereinafter;

Means. is provided for. assuring; the timing of the starting; and stopping ofthe pump I9 and the bleweniii; and the inflow of. fresh uncirculated cleaning; fluid. all at the proper timesso as to avoidiexplosigr s:irrthe air cleaning system itself j.

When. the blower; l0 and pump i9; are stoppedv after the system has-been in operation for some-- time, thewalls of the chamber 9,, the filters 25,

andtheshaft l5,andgimpellers lfiwillbe covered with cleaning fluids If. the. last. cleaning. fluid o; flow; to th hamber. 9. was recircula d by the pump I? it might contain some :residuum of;

dust; or solid; particles not separated from fluid inthe -decanter;28;. If; the; system. should remain outofoperation for-sometime the moisture-within, the chamber. 9, would. evaporate, leaving: a depositof; dust.- particlesv within the; chamber 9,

on;- the shaft l'&;and;the; impellers. [6. Certain kinds of dushfor, example;. that; including TNT particles, have such: tremendously explosive poteni ialities. that. there; would be. danger of an xplosion. occurrin if; the chamber 9' and theshafi and; impellers werenot. thoroughly wetted before. the; impellers and the: blower shaft start to run when the system is put in operation again; o. liminate his; dan er, means. are" provided for; automatically; and; serially. initiating operation; ofthe. shaft;- 15; and. the blower [B after the lapse. of: a. predetermined; period following delivermof-cleaninsfiuidto. the-chamber. 9'. Although innormal; operation t-he.cleaning fluid is thrown fromtheimpellers lfircentrifugally, the pump It! delivers.- fluid. at. sufficient pressure. to flow through; the impellers; l6- andintothe chamber 9- efore; thee shaft; lfiibeginsg to rotate. In this wayanymarticles whichhave remained on the chamber.- walls, or. on. theshait l5 and; impellers Iii;will".be. thoroughly;wetted, and willbe'washed downiiintog.thabasin.2B before theshaft l5 begins: to. turn'., throwing; off: off dry; particles of dust against the wallsbf-- thezchamberwith' dangerv of explosion is prevented.

15* fordelivering freshcleaning fluid to the cham- Consequently the centrifugal.

her for a predetermined period prior to stopping of the blower l and the impellers I6. Thus, when the system is to be 'put out of operation the pump stops, thereby discontinuing the delivery of recirculated cleaning fluid, and simultaneously the fresh water .control valve 22 opens automatically, causing fresh water to, be deliv-- ered by the impellers to all parts within'the chamber 9. .The blower and impeller shaft-continue to run and fresh water is delivered for a predetermined period at the close of which the blower stops and the valve 22 closes. The use of the fresh water exclusively, without any recirculated water, during the last part of the blower operation reduces to an absolute minimum the amount of dust which may remain in the chamber 9 after the fluid evaporates.

The control mechanism preferably also includes means such as a float controlled valve responsive to lowering of the cleaning fluid to a predetermined level in the decanter reservoir 28, for automatically opening the fresh water valve 22 and maintaining it open until the desired level in the reservoir 28 is restored. The control mechanism also preferably includes a safety device which disables all of the equipment when the fluid level in the reservoir 28 falls to another predetermined level somewhat lower than that whichcauses opening of the make-up valve 22,

The general construction and arrangement of the parts describedabove is similar to the construction and arrangement disclosed in Patent No. 2,539,344, previously referred to. In accordance with the present invention, the blower i8 is so operated or controlled that it is delayed in starting, or has a retarded pick-up which follows only after the shaft and impellers l8 have been in operation for a period sufficient to wet and wash the interior walls of the chamber 9 and the parts contained in the chamber. In the form shown in the drawings, the delayed or retarded starting of the blower is accomplished by providing an impositive drive such as aslip clutch or coupling in the connections transmitting drive from themotor II to the blower I8. Preferably, the clutch or coupling comprises a kinetic type fluid coupling interposed between the impeller shaft l5 and the blower l0. -Themotor II is carried on a mounting platform 38 which is secured to the upper ends of vertical supports 31, anchored at their lower ends on the top of the chamber 9 or any other suitable fixed part. The impeller shaft |5 extends from the bottom bearing ll upwardly through the blowerv structure and the coupling 35 for connection to the motor shaft by means of a flange coupling 38..

posed between the blower |8 and motor .|l.

Mounted within the casing 39-is'a vaned impeller rotor 40 formed with a sleeve 4| whichextends upwardly through anti-friction bearings 42 carried in a hub 43 formed on the casing 39. A packing gland 44 at the upper end of the hub ,43 prevents leakage of fluid from within the casing 39 between the hub 43 and sleeve 4|. Set screws 45 secure the sleeve 4| of the coupling impeller 40 to the hollow impeller shaft l5 so as to cause the impeller 40 and impeller shaft l5 to rotate-to gether. A packing gland 46 seals the upper end of the fit clearance space between the impeller shaft I5 and the sleeve 4|.

A driven rotor 41, formedwith vanes interspersed between vanes of the impeller rotor 40, is mounted within the casing 39, and is formed with an outer shaft in the form of asleev'e' 48 by which the rotor 4'! is supported and joumaled in' bearings 49 housed within a downwardly extend ing hub 50 on the casing 39. 'A packing gland 5| at the lower end of the sleeve 50 prevents leakage of fluid from within the casing 39, and between the sleeve 48 and hub 50.

The outer shaft or sleeve 48 of the driven rotor 41 extends downwardly beyond the packing gland 5| and into the hub of the rotor 52 of the blower It], being secured to the rotor 52 by a set screw 53. A packing gland 48 prevents leakage between the sleeve 48 and the shaft |5. The casing 39 is formed with a filler opening normally closed lowing the termination of the preceding period of operation. The impeller 48 of the fluid coupling 39, being positively connected to the shaft l5 by the set screws 45, will start to rotate and will be driven concurrently with the shaft I5 and the impellers I6. However, because of the impositive drive characteristics of the fluid coupling 39, the driven rotor 41 will not start to rotate im-- mediately when the driving rotor 40 begins to run, but will be started and accelerated with a delayed or retarded pick-up action, causing the blower rotor 52 to lag behind the impellers l6.

Consequently, no air will be moved through the chamber 9 until after the chamber walls and all parts contained in the chamber have been washed forcibly and thoroughly.

Figure 7 shows a preferred arrangement for controlling the operation of the pump |9, the impeller shaft l5, the blower HI, and the fresh water valve 22 in accordance with the desired sequence ortiming. Power for operating the motors H and 29 and the various control elements to be described later is derived from a three-phase supply line constituted by line conductors 55, 56, and 51 controlled by a main threepole service switch 58. The line conductors 55, 56, and 51 lead from the switch 58 through a triple contact relay switch 59 to the pump motor 28. Branch conductors 55 56, and 51 lead through a triple contact relay switch 88 to the motor H which drives the impeller shaft l5 and" the blower H1.

The fresh water valve 22 is adapted to be operated by a solenoiddevice 6| one side of' which isconnected to a branch line conductor 56 and the other side of which is connected to the control circuit which is to be described later.

Means is provided for automatically effectingenergization of the solenoid 8| to open the fresh water valve when the fluid in the reservoir 28 has fallen to a predetermined level requiring replenishment or replacement of fluid lost by evap-' oration. Other means is provided for respondis, available for diflusion within the chamber.

The equipment for controlling the adding of re-' placement fluid to the system or stopping of the system may include a float switch assembly 62 7. of: the kind disclosed and: claimed. in the copen'diing application of Thomas W'. Carraway, Serial No-..793,-'71'3, fi led. December 24, 194 7.. As shown in "Figurev 6, this equipment: includes a casing 63 whichmayconveniently be-mounted; on the reservoir- 28. movements in the casing 6-3, is formed with a radial arm- 65: connected to a depending. link 55 extending through afixed guide 61 for connectionyt'o. a; float. 68. Fast on the shaft 54 is a cal-n59 adapted, upon, lowering of thefiuidlevel in: the reservoir: 28;. to close a normally. open micro-switch 10 so. as to energize the solenoid 6| andaopeni the valve: 22. Also fast on the shaft 64 is a cam 1| which normally maintains amicroswitch. 12 closed. When. thefloat 6.8 descends to apredeterminedlevel, lower thanv that v at .whichstopping. operation of the entire system. in a.

manner tobe described later.

In; order toprepare the apparatus for service.

but; not actual-lyto start it, the line switch. 58

isclosed; Starting and stoppingv of the apparatus:

is controlledby a master switch, generally designated 13:, including two contact bars 14 and 15.:articulated by any suitable mechanism or linkage18 so as to. be movable to open and closed positions, simultaneously. In order to start the apparatus; the contact bars 14 and 15 are moved respectively downwardly and upwardly to closed positions. Closing of the contact bar 14 immediatelyenergizes the relay coil 59* of. the switch 59 lifting. the contact bars 59 and closing the switch: 59 toastart the: pump motor 29. The circuit for, energizing: the relay coil 59 includes the conductor 56:. the coil 59; conductors 1? and 18; the upper contact 14 of. the switch 13; con.- ductors 19, 80; and 8|; the lower cont-act arm of.arelayswitch 82;, conductors 83 and 8-1; the normally closed safety switch 12; a conductor 85; and the line conductor 55.

.Whenthe contactors. 14 and 15 of the switch 13 are. closed, starting the pump motor 2|) immedi-' ately as, described above, the motor I I will not be startediimmediately; buta. device, generally dessignatedv 86 for controlling the motor H, will be enabled: and will start a timing cycle. The device 85 maybe of any-of a number of known or commercia'lly availableconstructions characterized by being. capable of effecting a delayedtclosingv of the switch 82' after the lapsing. of a predetermined interval following; enabling of the device 86, and preferably further characterized by being capable ofeffecting opening of the switch 82 only after the: lapsing of: a. predetermined interval following: disabling of the device 86. The circuit for enabling: the control-device 86 includes the conductors56- and'56; a conductor 81'; the control device including a relay coil. 86 a conductor 88; thezlower contact. bar 15- of: the switch '53; the

' conductors Ti and 1-8; the upper contact bar 14-;

driverrto: deliver fluidto the hollow impeller shaft l5 -but during which the blower'and' shaft [5 have not been'running,v the cycling of the controldevice 86 is completed and the relay coil'86' is ener gized sufficiently to lift the contact unit 82*. This will complete" a circuit through the coil 69 of the switch 60-? so asto': lift the triple contactunit 89 and=closethe switch 69 to start the motor: H.

A shaft '64; journaled for rocking The circuit for energizing. the relay coil 6min-- cludes conductors 56. and156, abranch conductor 56*, thecoil a conductor 89, the lower bar of the contact:unit 82 *of the switch 82", the conductor 80, a conductor 91', the upperbar-of a contac-- tor unit 92 of a triple contact switch 92, the conductor 84 and -safety switch 12, and the conductors 85 and 55.

Thus-closing of'both contactors 14 and; 15 01. the switch 13 will, first,efie'ct' the starting of the pump motor 21!, and: thereafter, following thedetermined liquid' level has been reached and: the float 68 has descended accordingly, the cams 69:

and 11 will be rockedsufliciently to close the fluid make-up switch 10', but not to open the safety switch 12. Closing of the switch 10 will. effect energizing of the solenoids! to open the valve 22- to deliver additional and fresh fluid to the pipe I8, and thus torestore'the fluid inthe reservoir 28 toitsproper operatinglevel. The circuit thus closed by the switch 10 includes the conductors 56 and 56, the solenoid-61, conductors.

Stand 95, the make-up switch"),- the conductor 80, the conductor 9|, the upper bar of the contactor unit 92,the conductor 84:, the safety switch 12, and the conductors 85- and 55. When the fluid in the-reservoir 28-has been restored tothe desired operating level, the consequent raising of the float 68 willrock the cam. 69 to open the switch 10, thereby breaking thecircuit just'described, deenergizing the solenoid 61 and closing the valve 22.

If the-supply of 'Washing fluid should fail during an operating period; thefiuid ins the reservoir 28 eventually would fall toa: level somewhat be-- low the level at which the switch HI-is closedin the manner described above. float 68 to this lower-level will rock the cam'rf suificiently to-open the normally closed safety switch 12, thereby breaking all of the circuits described above, and thusdeenergizing the coils 59 86 and 60 so that the: motors 2'0 and Itwill be stopped. This-preventsoperation:of the apparatus orv any of its parts when no cleaning fluid is available.

If the level of. fluid in thereservoir' 28 should fall due-toevapo'ration or' leakage when the systemis not in operation; closing of the floatoperatedswitch 10will effectenergizing of: the solenoidifl to open the valve 22 and cause makeup liquid'tc-be-added. The: circuit for energizing the solenoid when the system is not operating, with the contactors positioned as shown in Figure 7-, includes conductors 5G an'd 56 the solenoid-'6 f, conductors 94 and 95, the make-up switch m1 conductors and 91", theupper-bar of' con-' tactor 92 conductor 84 the'safety switch 12, and

conductors 85 and 55.

In order to-stop-the apparatus, the switch 13 is operatedto lower: its-contact bar 15 and raise its contact bar 14, thusreturning the contact bars to the positions shown in- Figure 7.: This will breakthe circuit through the relay -coil59 immediately so" as to open theswitch 59 and stop the motor 2fl andlpfump I 9 Returning of: the: contact bars 14 and '1 5 of 'the switch-13 to=their Figure 'Tp'osi- Descending of the tions will break the circuit through the delayed action control device 66, but, because of the de- Ilayed action characteristics of this device previously referred to, the contact unit 62 of the i switch 82 will not be lowered immediately. At

the instant the switch 13 is restored to its Figure '7 position, and before the contact unit 82 is lowered, a circuit is completed through the relay coil 92 of the switch 92 to raise its triple bar contact assembly 92 .The circuit for energizing the relay 1 coil 92 includes the conductors 56 and 56, a

branch conductor 56, the coil 92s, a conductor 96, the lower contact bar 15 of the switch 13, a .conductor 91', the upper bar of the contact unit 82 conductors 96 and 84, the safety switch 12, and conductors 85 and 55.

When the contact bar 92 is raised by energiz- 2 ing the coil 92, the control of the make-up switch 10 over the solenoid valve 6|-22 is superseded,

' that is, the solenoid 6| is energized independentlyof the switch 10, and the fresh fluid valve 22 is opened so as to effect delivery of fresh, unused washing fluid to the hollow impeller shaft [5 following the stopping of the pump, and during continued operation of the impeller shaft- I5 and blower Ill. The circuit for independently energizin the solenoid 6| includes conductors 56 and 56 the solenoid 6|, conductors 94 and 95, the

middle contact bar of the contact unit 92 a conductor 98, the conductors 93 and 84, the safety switch 12, and conductors 85 and 55.

As previously explained, when the contactors l4 and T5 are returned to their Figure '7 positions,

the circuit is broken through the time control device 86, but the contact unit 82 remains raised for a predetermined interval during which the impeller shaft l5 and blower continue to run while the valve 22 is maintained open for the delivery of fresh fluid. At the close of the predetermined time interval, the contactor unit 82 returns to its Figure 7 position, thus breaking the circuit through the relay coil 60, and opening the switch 66 to stop the motor II, the shaft l5, and the blower 10. Simultaneously, the circuit is broken through the relay coil 92 so as to open,

the switch 92 and deenergize the solenoid 6|,

' thereby closing the valve 22 and terminating the delivery .of fluid to the impeller shaft l5.

In some instances it is desirable that the flow of fresh washing fluid be continued for a short while after the switch 82 has opened to stop the motor II. Accordingly, the switch unit 92 preferably has delayed opening characteristics such that the contactor unit 92 will remain raised for a predetermined period after the coil 92 has been deenergized. Any of a number of commercially known and available delayed opening switches may be used for this purpose.

It will be apparent that apparatus or systems embodying the invention are capable of efficiently invention in the form now preferred, it will be apparent that changes may be made in the arrangement of parts, and other physical forms of individual parts may be employed without departing from the invention. Thus it may be desirable in some installations to employ other than three-phase equipment, andin certain instances it may be to advantage to provide transformer equipment for placing the control circuits and relays under low voltage operation. It is intended that the scope of the invention be determined by the appended claims rather than by the specific disclosure of a preferred embodiment.

I claim:

1. In apparatus for removing dust or solid particles from gas, a removal chamber; a blower including a rotor for moving the gas through said chamber; a fluid diffusing impeller mounted to rotate in said chamber at a speed different from the speed of said blower rotor; a motor for driving said impeller; means for supplying fluid to said impeller for being thrown off centrifugally by said impeller to create a diffused spray of fluid contactible by the gas as it moves through the chamber; and means'for automatically starting and impositively driving said blower rotor only after said impellerhas been driven, whereby a diffused liquid spray will be created in said chamber before gas is moved therethro'ugh.

2. In apparatus for removing dust or solid'pa'rticles from gas, a removal chamber; a blower including a rotor for moving the gas through said chamber; a fluid diffusing impeller mounted to rotate in said chamber at a speed different from the speed of said blower rotor; a motor for driving said impeller; means for supplying fluid to said impeller for being thrown off centrifugally by said impeller to create a diffused spray of fluid said motor to said blower so as automatically to start and drive said blower rotor only after said impeller has been driven, whereby a diffused liquid spray will be created in said chamber before gas is moved therethrough.

3. In apparatus for removing dust or solid particles from gas, a removal chamber; a blower including a rotor for moving the gas through said chamber; a fluid diffusin impeller mounted to rotate in said chamber at a speed different from the speed of said blower rotor; a motorfor driving said impeller; means for supplying fluid to said impeller for being thrown off centrifugally by said impeller to create a diffused spray of fluid contactible by the gas as it moves through the chamher; and an impositive delayed action fluid clutch coupling for transmitting delayed starting drive impositively from said motor to said blower so as automatically to start and drive said blower rotor only after said impeller has been driven, whereby a diffused liquid spray will be created in said chamber before gas is moved therethrough.

4. In apparatus for removingdust or solid particles from gas, a removalfehamber; a blower including a rotor for moving the-gas through said chamber; a fluid diffusing impeller mounted to rotate in said chamber at a speed different from the speed of said blower rotor; a motor directly driving said impeller; means for supplying fluid to said impeller for bein thrown off centrifugally by said impeller to create a diffused spray of fluid contactible by the gas as it moves" through the chamber; anda kinetic type fluid coupling for transmitting impositive delayed starting drive from said motor to said blower so as automatioally to startand drive said blower rotor only .11. '5. :In apparatusforremoving dust or solid/particlesafromsgasi a removal chamber; a :motor; an

inner-shaft drivinglyconnectedxto saidmotor and extending into :said chamber; means. associated withsaid :shaft for throwing fluid in a diffused spray :in said chamber when said shaft is rotated; means :for supplying fluid torsaid Lfluid throwing means; an outer-shaft iournaled for rotation about the axis of and relatively to said inner shaft; :a blower including a rotor 'drivingly connected to said-'outershaft; and means for auto- ;matically-ximpositively startingand driving said outer-shaftwith respect to: said inner shaft and -thereby said blower rotor only after said inner shaft and said fluid throwin means have been driven; wherebya diffused liquid spray will be created in said chamber before gas is moved therethrough.

6.111 apparatus for removing dust or solid particles from gas, a.-removal chamber; a motor; en'innershaft drivingly connected to saidmotor and extending into said chamber; means associated with said shaft. for throwing .fluidzinia diffused spray int-saidichamber when said shaft is rotated; meansiforsupplying fluidito said fluid throwing means; an outer shaft journaled for rotation about the axis of and relatively to said inner-shaft; av-b1ower including a rotor drivingly connected to said outer-shaft; and a slip clutch :couplingimpositively connecting-said shafts for automatically starting and driving said outer shaft with respect-torsaid inner shaft and thereby said blowers-rotor 'only after saidiinner shaf-t. and said fluid throwing: means have been driven, whereby-a diffused-liquid spray will be created in 'said: chamber before' gas is moved therethrough.

7. -In apparatus for removing dust or solid :particlesfrom gas, a removalchamber; a motor; an innerrshaft directly drivingly connected to said motor and extending into said chamber; means associated with said shaft for throwing fluid in a diffused :spray in said chamber when saidshaft'is rotated; means for supplying fluid to said fluid throwing meansy-an outer shaft.

' 'ournaled' for rotation about the" axis of and relativelytto said inner shaft; a blower including a rotor *drivingly connected to said outer shaft; and a delayed action fluid clutch impositively connecting said shafts 'for automatically star ing and driving said outer shaft with respect to said inner shaft and thereby said blower rotor only after said, inner shaft and said fluid throwing means havebeen driven, whereby a difiusedliquid spray will beicreatedinzsaid chamber before gas .is movedtherethrough.

8. In apparatus for removing dust or" solid particles from gas, aremoval chamber; a motor; .an inner shaft ldrivingly connected to said onotor and extending into. :said chamber; means asso- -'ciated with said shaft for throwin fluidwin a difiusedsprayz'in said chamber "when said-shaft is rotated; meansfor supplying fluid to said fluid-throwing means; an outer shaft journaled :forrotationabout the axis of. and relatively to said inner shaft; a blower including a rotor drivinglyconnected: toisaidouter shaft; and a kinetic: type fluid coupling impositively connecting said shaftsfor automatically startingland driving said outer shaft with'respect to said inner shaft and thereby said blower rotor only after said inner shaft and: saidfluid throwing meanshave-been' driven, ,wherebyadifiused liquid spray will be createdin'saidphamber beforeigas is moved therethrough;

9. .In apparatus for removing dust or':so1id particles from gas, 'a removalrchamber; a motor; a hollow inner: shaft 'directlydrivingly connected to said motor and extending into 'said chamber;

' means for supplying "fluid to the interior of said have-been driven, whereby :a diffused liquid. spray will be; created in said; chamber before gas-is lmOVEd there'through.

10.:In apparatus for removing dust or solid particles from, gas, a removal chamber; :a motor;

azhollow :inner :shaft/driving-ly connected to "said motor and extendingcinto :said chamber; means for" supplying .fluid to the interior of said shaft; -impeller means on. 'said :shaft and communicating' with. the interior-thereof :for' receiving 'fluid and throwing it in .:a diffused :spray when said shaftis rotated; an outer shaft 'J'ournaled for rotation about the axis of and-relatively to said inner shaft; a blower includinga rotor drivingly connected to sai'd outer shaft; and raxkinetic type fluid-coupling impositively connecting said shafts for automatically starting and driving said outer shaft and therefrom driving said blower rotor only after said inner 'shaft and said impeller means have been driven, whereby a diffused liquid spray will becreated' in said chamberbefore gas is moved 'therethroug'h.

-11'.In apparatus for removing dust or solid particles from gas, a'removal chamber; a blower for moving'the gas through said chamber; a fluid diffusing impeller mounted to rotate in said flc'hamber; means for supplying fluid under pressureto said impellerfor being sprayed into said chamber 'by the fluid'pressure while'said impeller is stationary and for being thrown off centrifugally by said impeller during rotation thereof to createa diifused spray of fluid contactible by the gas as it moves through the chamber; time delaycontrolled means for starting rotative driving-of'saidimpeller after 'lapsing of a predetermined appreciable time following the start of operation of said fluid supplying means, whereby fluid will be sprayed into said chamber beforesaidimpeller is rotated; and means for auto- 'matically starting and driving said blower only after said impeller has been driven, whereby a diffused liquid spray will-"becreated in said chamber before gas :is moved therethrough.

12-.In apparatus forvremoving dust or solid particles from gas,a removal chamber; a'blower for moving the gas -through said chamber; a fluid diffusing impeller mounted to rotate in said chamber; means for supplying "fluid under pressure to saidimpeller for being sprayed into said chamber by the fluid pressure while said impeller is stationary and for being thrown off centrifugally'by said impeller during rotation thereof to create a diffused spray of fluidcontactible by 'the :gas as it moves through the chamber; time delayzcontrolled means for starting .rotative driving 'ofsaidimpeller afterdapsing of axpresdetermined appreciable time :following the start of. operation :of said fluid -.supplying: means, whereby fluid will be sprayed into said chamher before said impeller is rotated; and a delayed action fluid clutch for automatically starting and driving said blower only after said impeller has been driven, whereby a diffused ii uid spray will be created in said chamber before gas is moved therethrough.

13. In apparatus for removing dust or solid particles from gas, a removal chamber; a blower for moving the gas through said chamber; a fluid diffusing impeller mounted to rotate in said chamber; a pump for supplying fluid under pressure to said impeller for being sprayed into said chamber by the fluid pressure while said impeller is stationary and for being thrown off centrifugally by said impeller during rotation thereof to create a diifused spray of fluid contactible by the gas as it moves through the chamber; means for conducting fluid from said chamber back to said pump for recirculation; a source of fresh fluid; a normally closed valve for controlling delivery of fresh fluid from said source to said impeller; means for driving said pump and said impeller; means for automatically starting and driving said blower only after said impeller has been driven, whereby a diffused liquid spray will be created in said chamber before gas is moved therethrough; cut-oil means for stopping said pump; delayed action means operative in response to operation of said cut-off means for terminating driving of said impeller and said blower after the lapsing of a predetermined period following operation of said cut-ofi means; and means also responsive to operation of said out-- off means for opening said valve and maintaining it open during said period.

14. In apparatus for removing dust or solid particles from gas, a removal chamber; a blower for moving the gas through said chamber; a

fluid diffusing impeller mounted to rotate in said chamber; a pump for supplying fluid under pressure to said impeller for being sprayed into said chamber by the fluid pressure while said impeller is stationary and for being thrown off centrifugally by said impeller during rotation thereof to create a diffused spray of fluid contactible by the gas as it moves through the chamber; means for conducting fluid from said chamber back to said pump for recirculation; a source of fresh fluid; a normally closed valve for controlling delivery of fresh fluid from said source to said impeller; means for driving said pump and said impeller; a delayed action fluid clutch for automatically starting and driving said blower only after said impeller has been driven, whereby a difiused liquid spray will be created in said chamber before gas is moved therethrough; cut-off means for stopping said pump; delayed action means operative in response to operation of said cut-on means for terminating driving of said in.- peller and said blower after the lapsing of a predetermined period following operation of said cut-off means; and means also responsive to operation of said cut-ofi means for opening said valve and maintaining it open during said period.

THOMAS W. CARRAWAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 810,451 White Jan. 23, 1906 976,246 Allberger Nov. 22, 1910 1,238,447 Severy Aug. 28, 1917 1,650,292 Miscampbell Nov. 22, 1927 

